Central vacuum systems for homes and commercial buildings have been provided for many years and generally include a central vacuum power unit and dust receiving chamber located in a basement or closet of the building with vacuum conduits routed throughout the building from the central vacuum power unit to outlets conveniently located throughout the building. An operator merely carries a hose with him or her, moving from outlet to outlet while cleaning. The central vacuum cleaning power unit requires high voltage to efficiently power the suction motor which in the United States this is a 110/115 volt AC standard. The central vacuum motor can be turned on either at the unit or more conveniently, at wall switches at various locations in the building to which 110/115 volt AC power is routed to complete a circuit to the vacuum motor.
Alternatively, systems have been devised to send a start signal to the vacuum cleaning motor when an end of the portable cleaner hose is inserted in a wall outlet. Examples of such systems are shown in our earlier patents, U.S. Pat. Nos. 3,076,068 and 4,336,427. As disclosed therein, a low voltage wiring, such as 24 volt DC power, is routed to the wall outlet and either a switch is activated when the hose is plugged into the outlet, or spaced pins are provided which complete a circuit when a metal hose end coupling of a portable vacuum hose is inserted into the wall outlet. In these systems, a start signal is sent through the low voltage wiring to a motor controller associated with the central vacuum cleaning power, unit to start the main vacuum motor. Low voltage power, such as 24 volt DC power, has become the standard in the industry for such outlet switches because of safety factors and to avoid the risk of electrocution. Cleaning tool attachments may be connected to the ends of the vacuum hose such as a carpet cleaning brush. These carpet brushes are a combination wide vacuum nozzle with a rotating brush powered by an electric motor located at the hose end and a sealed unit. These carpet brushes also utilize high voltage electrical power, such as 110/115 volt AC.
To provide 110/115 volt AC power at the hose end, a separate electrical cord extends from the hose end to a building power electrical wall outlet which is preferably co-located with the vacuum outlet and which is installed in new construction buildings at the same time as installation of the vacuum hose outlet. Hose component manufacturers have provided vacuum hoses with two wire electrical lines for several years to avoid the obvious inconvenience of having completely separate electrical lines and vacuum hoses. With the development of unitary vacuum hoses and electrical lines, combination electrical outlet and vacuum outlet receptacles have been developed, such as shown in U.S. Pat. No. 4,664,475. These systems employ both the automatic turn-on and turn-off function of the wall outlet with the low voltage power control line and the carpet sweeper brush functions provided by the high voltage power line. When the vacuum hose is inserted into the wall outlet, the vacuum motor at the central vacuum power unit is operating. To stop the operation of the central vacuum system motor, the hose end must be pulled from the wall outlet. This can become an unwieldy chore for the operator, as the hose lengths are often quite long.